Chapter 26Urinary System

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Functions:

1.Excretion: removal of waste products from body fluids

2.Elimination: discharge of waste products from body

Chapter 26Urinary System

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Consists of the

•Kidneys: produce urine

•Ureters: pathway of urine from kidneys to bladder

•Urinary bladder: muscular sac for temporary storage of urine

•Urethra: urine removal pathway

Location of Kidneys

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Located on either side of the vertebral column (T12-L3)

Superior surface is capped with the adrenal gland.

Protection of Kidneys

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Renal capsule: inner layer of collagen

Adipose capsule: thick layer of adipose tissue

Renal Fascia: outermost layer of collagen

Kidney Structure

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Kidney Structure

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2 layers:

1.Cortex: superficial portion, contains nephrons

• Nephron: microscopic, tubular structures that beings urine production

2. Medulla: consists of 6-18 renal pyramids

•Renal lobe: renal pyramid + renal cortex

• where urine is produced

•Renal Pelvis: large chamber which connects the renal lobes to the ureter

Functions of the Kidneys

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• Removal of metabolic wastes from the blood and excretion to the outside of the body

• Regulation of blood pressure, calcium ion absorption, and the volume, composition, and pH of the blood

Renal Blood Vessels

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Renal Blood Vessels

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Renal Blood Vessels

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• Kidneys receive 20-25% of total cardiac output

•Receives blood from the renal artery segmental arteries interlobar arteries arcuate arteries interlobular arteries afferent arterioles deliver blood to nephrons interlobular veins arcuate veins interlobar veins renal vein

Structure of a Nephron

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Structure of a Nephron

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•Renal tubule: long pathway that starts at the renal corpuscle

•Renal corpuscle: contains a glomerulus, where the capillaries are found, where filtration takes place

Pathway of filtration of a Nephron

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•Blood filters into the afferent arteriole Renal corpuscle

(Glomerulus and Bowman’s capsule) Proximal convoluted

tubule (where reabsorption of water, ions, organic nutrients)

down Renal tubule Loop of Henle ( further reabsorption

of water) up Renal tubule Distal convoluted tubule

(secretion of acids, drugs, toxins) collecting duct

Papillary duct (all excess waste—urine– to minor calyx

major calyx ureter

Glomerular Capsule

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stop

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Juxtaglomerular Apparatus

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Cortical and Juxtamedullary Nephrons

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• cortical nephrons• 80% of nephrons• located close to the surface of the kidney

• juxtamedullary nephrons• regulate water balance• located near the renal medulla

Urine Formation

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• nephrons remove wastes from the blood and regulate water and electrolyte concentrations

• urine is the final product of the processes of:

• glomerular filtration

• tubular reabsorption

• tubular secretion

Urine Formation

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• Glomerular Filtration• substances move from blood to glomerular capsule

• Tubular Reabsorption• substances move from renal tubules into blood of peritubular capillaries• glucose, water, urea, proteins, creatine• amino, lactic, citric, and uric acids• phosphate, sulfate, calcium, potassium, and sodium ions

• Tubular Secretion• substances move from blood of peritubular capillaries into renal tubules• drugs and ions

Urine Composition

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• about 95% water

• usually contains urea, uric acid, and creatinine

• may contain trace amounts of amino acids and varying amounts of electrolytes

• volume varies with fluid intake and environmental factors

Ureters

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•Leave the kidneys •25-30 cm long•parallel to vertebral column• in pelvic cavity, join urinary bladder

Urinary Bladder

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• hollow, muscular organ located within the pelvic cavity, posterior to the Symphysis pubis

•Can hold up to a liter of urine (rugae)

Urinary Bladder

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• the internal floor of the bladder includes a triangular area called the trigone •Internal urethral sphincter: provide control over bladder

Urethra24

• tube that conveys urine from the urinary bladder to the outside of the body

• Men: 18-20 cm

• Connects to the prostate/ejaculatory ducts

• Female: 3-5 cm

•External urethral sphincter

•UTI

•Incontinence

Life-Span Changes

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• kidneys appear scarred and grainy • kidney cells die• by age 80, kidneys have lost a third of their mass• kidney shrinkage due to loss of glomeruli•harder for kidneys to clear certain substances• bladder, ureters, and urethra lose elasticity• bladder holds less urine

Formal Lab Write-up DUE • Heading

• Name, title (be creative), date

• Problem• What are you testing and

why?

• Hypothesis• What do you think you will

discover after the experiment?

• Materials• LIST of every tool required

• Experiment• STEP BY STEP instructions

on what happened

• Observations• What did you see, smell,

hear?

• Discussion • What do you know NOW?

• Conclusion• Summary of what happened,

what errors occurred, why this experiment was useful

26

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Matching

1. Cortex

2. Bowman’s Capsule

3. Loop of Henle

4. Renal Pelvis

5. Nephron

6. Ureter

7. Hilus

8. Renal Capsule

a. Functional Unit of the Kidney

b. Transports Urine to Bladder

c. U-shaped tubule

d. Covers the surface of the kidney

e. Surrounds glomerulus

f. Outer layer of kidney

g. Area on kidney where blood vessels, nerves, lymphatics, and ureters enter/exit

h. Drains major calyx

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Matching

1. Cortex (F)

2. Bowman’s Capsule (E)

3. Loop of henle (C)

4. Renal Pelvis (H)

5. Nephron (A)

6. Ureter (B)

7. Hilus (G)

8. Renal Capsule (F)

a. Functional Unit of the Kidney

b. Transports Urine to Bladder

c. U-shaped tubule

d. Covers the surface of the kidney

e. Surrounds glomerulus

f. Outer layer of kidney

g. Area on kidney where blood vessels, nerves, lymphatics, and ureters enter/exit

h. Drains major calyx

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Short Answer

• What are some anatomical differences with the male versus female urinary structures and how do they affect the physiology?

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Short Answer

• What are some anatomical differences with the male versus female urethra and how do they affect the physiology?

• Males have longer urethra = fewer UTI’s, less urgency for urination

• Ejaculatory/prostate ducts connect to males urethra = urethra doesn’t just carry urine

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32How do the following tests relate to a urinalysis?

Leukocytes

Nitrites

Protein

pH

Blood

Specific Gravity

Ketone

Bilirubin

Glucose

33Meaning

Leukocytes Only found in individuals who are fighting a bacterial/viral infection

Nitrites Only found in individuals with significant infections

Protein Found in individuals with kidney disease/damage

pH If increased ketone levels, there will be a more acidic urine

Blood Only present if trauma, UTI, or recent menstruation

Specific Gravity Degree of concentration/dilution of urine (amount of excess water)

Ketone Positive with excessive lipid breakdown

Bilirubin Rare-breakdown of hemoglobin

Glucose Excess-hyperglycemia